Charge forming device



March 1, 1932. w. HTEETER 1,847,732

CHARGE FORMING DEVICE Filed Oct. l5, 1928 2 Sheets-Sheet l 0 anw M m M 1l 7 l w M o J Z 4 m w 2 z 28o/o /20 7 22 .4/ O 7- u @M 4 b 5 K M 0 2 8H- HH A w a w 4 ww 5 n 4l ./0 Y 4/ M uw ,aM/o hun... HHH@ M 40 5 426l/Prd7 533` Mmm a a Mm H M Z8 ,n .uw a mw M 1 a, v y 8).U......l....|.....|. l M. H 4 A e .0)1 3 5 W s 4 2 44@ 2 March l, 1932.w. H. TEETER 1,847,732

CHARGE FORMING DEVICE Filed Oct. l5, 1928 2 Sheets-Sheet 2 O"IllPatented Mar. 1, 1932 UNITED STATES 'PATENT oFElc-E WILFOBD H. OFDAYTON, OHIO, ASSIGNOB., BY ASSIGNMENTS, TO DELCO PRODUCTS CORPORATION,F DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FOBHING- DEVICE.Application led October 15, 1928. Serial No. $12,510.

This invention relates to charge forming devices for internal combustionengines and more particularly to that type of charge forming devicewhich comprises a plurality of primary mixing chambers, one for eachintake port of the engine, having a commonl source of fuel supply andcooperating respectively with a plurality of secondary mlxing chambers,each located adjacent an engine intake port, each of said secondarymlxlng chambers receiving primary fuel mixture from one of the primarymixing chambers and receiving additional air through an air manifoldwhich supplies air to all the secondary mixing chambers.

Examples of this type of charge forming device are disclosed in theprior application of Fred E. Aseltine, Serial No. 83,979, filed January26, 1926, andthe Patent of Fred E. Ascltine and Wilford H. Teeter, No.`

In devices of this character heretofore,

known, as for example those shown in the above mentioned applications,means are provided to enrich the mixture on opening movements of thethrottle to supply a mixture of the proper proportions to mostsatisfactorily operate the engine during the acceleration period. Ityhas been found that ya leanenmixture is desirable during theacceleration period when the engine is hot than when said engine is coldand the principal object of the present invention is to provide meansfor enriching the mixture on opening movements of the throttle to supplythe desired mixture =for acceleration and to provide thermallyresponsive means for. controlling said mixture enriching means so thatthe latter is effective to supply a richer mixture nwhen the engine `iscold than when said engine l-is relatively warm.

More speciically, it is an object of the present invention to providemeans for retarding the opening of the air valve-during openingmovements of the throttle to enrich the mixture for acceleration and toprovide thermally responsive means for controlling the operation of saidretarding means.

According to the present invention, these objects are accomplished bythe provision of a dash ot for retarding the opening movement oft e airvalve provided with a movable cylinder which is moved by the throttlethe retarding effect of said dash pot as the throttle is opened andthermally responslve means is provided associated with the cylinder ofsaid dash pot to regulate the escape .during its opening movement toincrease Y the engine is cold, either in cold weather or vwhen 1t isfirst started, the valve is held closed or nearly closed by thethermo/static element, but as the engine warms up after running for anyappreciable time, or when' the weather 'is hot, the valve is adapted tobe opened to a greater degree by said thermostatic element to permitflel to esca from the dash valve isl opened.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of one form of the presentinvention is clearly shown.

In the drawings:

Fig. 1 is a vertical longitudinal section through -a charge formingdevice in which the present invention is embodied.

Figs. 2 and 3 are detail sections on the lines 2-2 and 3 3 of Fig. 1':

Figure 4 is a side elevation of the carburetor unit, showing themechanism for operating the dash pot cylinder.

Figures 5 and 6 are detail views of this mechanism. The referencenumeral 10 indicates an air pot more rapidly as the a1r d manifold whichis provided with three outlet y.

attaching Bange '14 adapted to be secured to 1W the engine block in theconventional manner.

49 described in detail in this application.

. 55 'ping of said column of fuel.

The air manifold has secured to the lower side thereof by any suitablemeans, a frame 16 supporting a constant level fuel chamber 18 attachedto said frame by screws 20. Fuel is conducted to said fuel chamberthrough a conduit, which is not disclosed herein and the flow of fuel tosaid chamber is controlled by a oat 22 operating in the usual manner.

A distributor block 24 is secured to the upper side of the air manifoldin any desirable way and said distributor block has a plurality ofprimary mixing chambers 26 formed therein, as indicated in the drawings.The specific construction of the distributor block and the means forconveying the fuel mixture formed therein to the secondary mixingchambers will be described later.

To conduct fuel from the fuel chamber 18 to the distributor block thereis provided a tube 28 screwed into a passage 30 formed in the wall ofthe air manifold. Tube 28 extends downwardly into the fuel chamber toceived in the passage 30 is a sleeve 34 partly closed at its lower endand open at its upper end, an orifice 35 being formed in the lower endof said sleeve to provide a valve seat with which asuction operatedvalve 36 received in said sleeve cooperated. This valve forms atwo-stage metering Valve which is illustrated in detail and fullydescribed in the above mentioned patent and need not be Seated on top ofthe sleeve 34 is a check valve 38 which prevents the fuel in the tube 28flowing back toward the fuel chamber. It has been found that undercertain conditions of operation, as for instance when the engine speedis suddenly reduced, the resulting reduction in suction on the column offuel between the fuel chamber and the primary mixing chambers wouldpermit this column to drop suiiiciently to cause a temporary fuelstarving of the engine unless means were provided to prevent such anoccurrence, and it is the function of the above mentioned check valve toprevent the drop- The upward movement of the check valve is limited byfingers 40 projecting from a sheet metal collar 41 received in anenlargement in the passage 30.

The lowerface of the distributor block is provided with a groove 42which constitutes a fuel distributing canal and conducts liquid fuelfromthe passage 30 to each of the primary mixing chambers above referred to.A removable fuel metering plug 44r conducts fuel from the canal to eachof the primary mixture passages, as indicated in Fig. 2 and an air inletbushing 46 admits air to each of the primary mixture passages adjacentsaid metering plugs, as shown in Fig. 3. In so far as the presentinvention is concerned, the specific formation of these air inletbushings is not material and reference is made, therefore, to Patent No.1,762,463 for a more detailed description.

To secure equalization of pressure in the various primary mixingchambers, a passage 48 is provided to place all of said chambers incommunication with each other. This passage is inthe form of a groove orchannel cut in the bottom face of a plate 50 secured in any suitablemanner to the upper face of the distributorblock. The passage 48communicates with each primary mixture passage through holes 52 bored inthe top of said distributor block. 'Each primary mixture passage isconnected with one of the branches of the main air manifold by aconduit, this construction being fully shown and described in the abovementioned patent and forming no part of the present invention. Thepassage connecting the primary mixture passage with the branch 12 of theair manifold is disclosed herein and comprises a vertical bore 54 formedin the distributor-block which registers with a bore 56 in the wall ofthe manifoldbranch 12.

The construction of the secondary carburetors is identical, and thatwhich is located in the branch 12 of the manifold is shown in theFig. 1. A large Venturi tube 60 is held in position in the manifold bymeans of a set screw 62, the tapered end of which cooperates with arecess 64 in the outer surface of the venturi. The venturi is providedwith a channel 66 in its outer surface which registers with the bore 56above referred to and a slot 68 in the wall of the venturi at the pointof the greatest depression therein permits passage of the primarymixture from the channel 66 to the interior of said Venturi` tube. Therich mixture entering the venturi through said slot is mixed withadditional air and the resultant mixture is drawn into the engine by thesuction therein, the flo-w of said mixture being controlled by athrottle valve 70 secured to a shaft 72. Each outlet branch of themanifold is provided with a Venturi tube and throttle, the throttlesbeing operated simultaneously by a mechanism fully described in thecopending application above referred to.

lVhen the throttles 70 are only partially opened, there is but a smallquantity of air flowing through each manifold branch at relatively lowvelocity. Because of the low velocity of air flow there is a tendencyfor fuel particles to settle with out the fuel mixture and collect onthe manifold wall resultingin uneven fuel distribution. To overj comethis tendency each branch of the manifold is provided with an automaticrestrictmg valve which opens in accordance with the velocity of theentering air and causes the entering mixture to pass said valve atrelatively high velocity under all operating conditions. Each of saidvalves is mounted in a sleeve 74 inserted in the manifold branch andextending into the engine intake port when the device is assembled. Thesleeve 74 is held in place by means of ears 76 cut out of the wall ofsaid sleeve, the ears being'clamped between the manifold and the enginewhen the manifold is attached thereto. The sleeve 74 is provided with atransverse pin 78 on which two Hat valves 80 are pivoted.y These valvesare urged toward closed position by a spring 82 which is connected tothe valve as indicated in Fig. 1. The lower wall of the'sleeve isprovided with a projecting lip 84 which is held back in the sleeve asshown in Fig. 1, forming a space between said lip and the lower wall ofthe sleeve. Holes 85 are provided toconnect the space between the lipand the sleeve with the intake passage and to permit passage of the fuelmixture for idling when the valves 80 are closed, and also to enable anyfuel which-precipitates from the fuel mixture to flow back into themixture stream to be re-atomized.

To admit air to the air manifold 'an air inlet horn 90 is secured in anysuitable way to to the upper wall of the manifold casting over anopening 92 in the said wall. The flow of air is controlled by valve 94normally held against its seat 96 by a spring 98 received between thevalve and a flange 100 projecting from the lower en'd of a sleeve 102which is slidably mounted on a stationary guide sleeve 104 supported bya spider 106 secured by screws 108 to the air horn. The

guide sleeve limits the opening movement of'the air valve and theslidable sleeve is adapted to be raised by amechanism not illustratedherein to a position where its upper end engages theair valve to holdsaid valve closed when it is desired to choke the engine to facilitatestarting. In order to enable the parts to vbe assembled, the bottom Wallof the manifold is provided with an opening 110 which is adapted to beclosed when the device is assembled by a packin washer 112 secured to ametal plate 1,14 fixe in the lower end of the guide` sleeve.

To enrich the fuel mixture for acceleration and to prevent fluttering ofthe air valve on opening movements of the throttle the opening of saidvalve is retarded by a liquid dash pot as shown in Fig. 1. This dash potcomprises a cylinder 120 slidably received in a guide 122 cast integralwith the frame 16. Holes 124 and 126 are provided in the guide endcylinder respectively below the fuel level in the ioat chamber, saidholes registering with each other when the cylinder is in its normallowered position to permit passage of the liquid fuel from the fioatchamber to the interior of the dash pot cylinder. The cylinder isadapted to be lifted to increase the retarding effect of the dash pot bymeans which will be described presently.

Cooperating with the cylinder is a piston 128 mounted on the lower endof the air valve stem 130 in the manner described in the above mentionedcopending applications. A bypass 132 comprising a pipe secured in thewall of the cylinder 120 has its upper end normally covered by the dashpot piston but is uncovered during downward motion. of said piston topermit passage of the fuel from the lower end of the cylinder around thepiston and partially relieve the retarding action of the dash pot whenthe air valve is partially open. j

When the throttles are opened to accelerate the engine and increase thespeed of the vehicle, the manifold suction is communicated to the lowerside of the air valve and is effective to open said valve and move thedash pot piston downward. The retarding effect of the dash pot greatlydiminishes as the piston moves downwardly and the bypass is beinguncovered. The relation of the by-pass to the piston determines thediminution of the retarding effect on the opening movement of the airvalve, and this reduction is varied automatically according to theposition of the throttle. The greater the initial opening of thethrottles at the time they are further opened to increase the speed, theless will be the retarding action. This variation is necessary becauseless retarding of the air valve would be required when accelerating froma 20 to a 25 mile per hour speed than from a 10 to 25 mile per hourspeed, assumvided with a flange 140 which is adapted to be engaged bypins 142 projecting inwardly from eachof the arms 144 of a bifurcatedlever secured to the rock shaft 146, which is operated by means fullydisclosed in the above mentioned patent, to lift the cylinder onopening` movement of the throttle. The means Ifor lifting the dash potcylinder through the medium of the throttle includes, briefly, an arm145 secured by a clamp or in any other suitable way to the tube 72 towhich the throttle is fixed. Pivoted on a pin 147 projecting from saidarm is an arm 149 having a cam slot 151 therein, the position of saidcam slot relative to the arm 145 being controlled by a set screw 153threaded in a gaging arm 149. The cam slot engages a pin 157 in the endof arm 159 pivoted on the rock shaft 146 outside the housing. Projectingfrom the arm 159 is a lug 161 in which a screw 163 is threaded. Thisscrew has a reduced portion extending through a hole in the end of anarm 165 secured to the shaft 146, while a spring 167 surrounds thereduced part of the screw between the lug 161 and arm 165. Obviously asthe throttle is opened the cam slot through the medium of pin 157 rocksthe arm 159 downwardly compressing the spring 157 and through arm 165rocking the shaft 146 to lift the dash pot cylinder as described. Thelifting of the cylinder as described will increase the resistance to thedownward motion of the piston and has been found desirable because whenthe throttle is opened slowly the downward movement of the piston isslow and there is so much leakage of fuel past the piston that theretarding effect of the dash pot on the opening movement of the airvalve is largely eliminated. When the cylinder is moved upwardlysimultaneously with the downward movement of the piston, however, ittends to displace more fuel than can escape by leakage and retards theopening movement of the air valve to the extent desired.

Retarding of the opening of the air valve forms a richer than normalmixture for acceleration for two reasons. First, of course the amount ofair entering the carburetor is reduced, decreasing the-'proportion ofair in the mixture. Also the difference in pressure between the ends ofthe primary mixture conduits is increased resulting in greater suctionat the jets, greater fuel flow, and a reduced interval of time requiredto convey the enriched primary mixture of the secondary mixing chambers.The mechanism described inthe foregoing pages and the function thereofis all described in full detail in the above mentioned patent. Y

As has been stated previously, it has been found desirable to controlthe retarding effect of the dash pot in accordance with the temperatureof the engine and to accomplish this result the lower end of the dashpot is provided with a hole 150 which is normally closed by a valve 152supported by a bi-metallic, thermostatic element 154 in the form of a U-shaped flat spring, which is received on a pin. 156 projecting from alug 158 which may be either cast with the bottom of the dash pot orsecured thereto in any desirable manner. The thermostatic element 154 isreceived between the lower end of said dash pot and an adjusting screw160 threaded in an arm 162 projecting from the dash pot, -said screwbeing adapted to engage one of the ends of the U- shaped member. Byvariably adjusting said screw, the pressure exerted by the thermostaticmember 154 on the valve 152 mav be controlled as desired and the normalposition of the valve may be regulated. It will be ob- `ber into whiching the fuel to escape from the dash pot more rapidly as the pistondescends. This reduces the retarding effect of the dash pot and allowsthe air valve to open more rapidly, admitting a greater quantity of airto the mixing chambers per unit of time and forming a leaner mixturethan when the valve 152 is closed. While the above described thermallyresponsive valve is particularly desirable in the form of charge formingdevice shown herein, its application is in no way limited and it may beemployed in any carburetor or in any dash pot per se in which it may befound desirable.

Also when the valve is in its closed or nearly closed position and theopening of the air valve is retarded as much as possible the pressuredifferential between the ends of the primary mixture conduits isincreased and the suction at the jets is increased resulting in theformation of a richer primary mixture than when the valve is open and avreduction in the time interval required to convey said mixture to thesecondary mixing chambers, resulting in better acceleration when theengine is relatively cold.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adapted, all coming within the scope of the claimswhich follow.

Vhat isy claimed is as follows:

1. A charge forming device for internal combustion engines comprising aprimary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamber into which said primary mixture passagedelivers, an air valve regulating the flow of air into the mixingchamber, means for retarding the opening of said valve and thermallyresponsive means for controlling the effect of said retarding means.

2. A charge forming .device for internal combustion engines comprising aprimary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamsaid primary mixture passage delivers, an air valveregulating the flow of air into the mixing chamber, means for retardingthe opening of said valve, means operated by the throttle for varyingthe effect of said retarding means, and thermally responsive means forvarying the effect of said retarding means.

3. A charge forming device for internal combustion engines comprising aprimary mixture passage, means for supplying fuel andsair thereto, asecondary mixing chamber into which said primary mixture passagedelivers, an air valve regulating the iow of air into the mixingchamber, means for retarding the opening of said air valve, means forincreasing the retarding elfect of said means as the throttle is openedand thermally responsive means for controlling the retarding effect ofsaid means.

' 4. A charge forming device for internal combustion engines comprisinga primary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamber into which said primary mixture passage de-llivers, an air valve regulating the liow of air -into the mixingchamber, a dash pot for retarding the opening `of the air valve, meansoperated by the throttle for varying the resistance of the dash pot andthermally responsive means for varying the resistance of the dash pot.

5. A charge forming device for internal combustion engines comprising aprimary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamber into which said primarymixture passagedelivers, anV air valve regulating the flow of air into the mixingchamber, a dash pot for retarding the opening of the air valve, meansfor increasing the resistance of the dash pot as the throttle is openedand thermally responsive means simultaneously effective to control theresistance of the dash pot.

6. A charge forming devicefor internal combustion engines comprising aprimary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamber into which said primary mixture passagedelivers, an air valve regulating the flow of air into the mixingchamber, a dash pot having a movable cylinder and piston for retardingthe openin of the air valve, means operated by the t lrottle for liftingthe cylinder to increase the resistancevof the dash pot and thermallyresponsive means effective throughout the movement of said cylinder forvarying the resistance of said dash pot.

7. A charge forming device for internal s combustion engines comprisinga primary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamber into which said primary mixture passagedelivers, an air valve re ulating the lloW of a1r into the mixing chamr, a dash pot having a movable cylinder and piston for retarding theopening of the air valve, means operated by the throttle for lifting thecylinder to ine crease the resistance of the dash pot and thermallyresponsive means carried by said cylinder and elfective in any positionof said cylinder to vary the resistance of said dash ot. v P 8. A chargeforming device for internal combustionengines comprising a primary andair thereto, a seconda mixing chamber into which said 1primary mixturepassage delivers, an air va ve regulatin the iow of air into the mixingchamber, a 'quid dash pot for ret-arding the opening of the air valve, avalve `for controlling escape of liquid from said dash pot and thermallyresponsive' means i for positioning said valve. a

9. A charge forming device for internal combustion engines comprising a'primary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamber into which said primary mixture passagedelivers, an air valve regulating the ilow of air into the mixingchamber, a liquid dash pot for retarding the opening of the air valve, avalve for controlling escape' of liquid from said dash pot, thermallyresponslve means for positioning said valve and means'for regulating theaction of the thermally responsive means.

10. A charge forming device for multicylinder internal combustionengines comprising a plurality of primary mixture passages, a pluralityof secondary mixing chambers into which said passages deliver, means forsupplying fuel .and air to said mixture passages, an air valvecontrolling admission of air to all of said secondary mixing chambers,means for retarding the opening of said air valve to increase thesuction in all of said mixture pas sages to enrich the mixture foracceleration, and thermally responsive means controlling the effect ofsaid retarding means.

1l. In a carbureter having a suction op- 10o erated air valve, a dashpot for controlling said air valve comprising a cylinder and a pistonmovable therein, means admitting liquid to said cylinder and thermallyresponsive means controlling the escape of liquid from 105 said cylinderwhereby the resistance of said dash pot may be regulated.

12. In a carbureter having a suction operated air valve dash pot forcontrolling said air valve comprising a cylinder and a. piston 110movable therein, means admitting liquid to saidY cylinder and thermallyresponsive' means controlling the escape of liquid from said cylindercomprising a thermostatic element sup- R ported on said cylinder and avalve carried mixture passage, means for supplying fuel CERTIFICATI; 0FCORRECTION.

Patent No. 1,847,732( March 1, 1932.

i wlLFoRD H. TEETER.

lt is hereby certified that error appears in the printed specificationofthe above numbered patent requiring correction as follows: Page 5,line 109, claim l2,4 after "valve" insert the Comma and article a"; andthat the said Letters Patent should be read with this correction thereinthat vthe same may conform to the record ofv the case in the PatentOffice.

Signed and sealed this 7th day of February, A. D. 1933.

M. J. Moore, (Seal) 3 Acting Commissioner of Patents.

